In the past, control devices for natural gas fired infrared heaters which have pilot burners have required shut off of only the supply of gas to the heater in event of failure of ignition. The gas supply has continued to flow to the pilot and released therefrom to the ambient. This small amount of gas has been considered harmless, particularly since it is lighter than air and flows upwardly.
However, local or state government regulations have required that both the heater and pilot gas supply be cut off after failure of ignition for a predetermined time. In the gas of propane gas, which is heavier than air, the time specified is ninety seconds.
The present invention provides a control system which will safely satisfy such regulations.